It is known that in a gas turbine engine a vane wake forms as the gas passes between the vanes. This vane wake passes to and through the rotating blade stage on to the second stage vanes. It is further known that vibration can occur in the various blades and vanes because of the pulsations occurring as the gas passes the rotating blades.
It has also been thought that the wake impingement on the second stage vanes themselves reduced the efficiency of the gas turbine.